CVE-2023-21835Network attack vector

Service interruption via cookieless DTLS resumption

Published Jan 17, 2023 · Updated May 28, 2026

Denial of service in JSSE in Oracle Java SE 11.0.17, 17.0.5, and 19.0.1 allows remote attackers to interrupt service via DTLS. The SunJSSE DTLS implementation omits the HelloVerifyRequest cookie exchange for resumed handshakes, processing them without first verifying peer return routability. Reachability requires attacker-controlled DTLS input through sandboxed untrusted code or a component API; the bounded consequence is partial service interruption.

CVSS severity5.3
Medium
EPSS probability1.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in JSSE in Oracle Java SE 11.0.17, 17.0.5, and 19.0.1 allows remote attackers to interrupt service via DTLS. The SunJSSE DTLS implementation omits the HelloVerifyRequest cookie exchange for resumed handshakes, processing them without first verifying peer return routability. Reachability requires attacker-controlled DTLS input through sandboxed untrusted code or a component API; the bounded consequence is partial service interruption.

The record

CVE
CVE-2023-21835
Published
Jan 17, 2023
Updated
May 28, 2026
Vendor
Oracle Corporation
Product
Java Platform, Standard Edition (Java SE)
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 17, 2023CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Oracle GraalVM Enterprise Edition:20.3.8
  2. Affected versionversion=Oracle GraalVM Enterprise Edition:21.3.4
  3. Affected versionversion=Oracle GraalVM Enterprise Edition:22.3.0
  4. Affected versionversion=Oracle Java SE:11.0.17
  5. Affected versionversion=Oracle Java SE:17.0.5
  6. Affected versionversion=Oracle Java SE:19.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · Java Platform, Standard Edition (Java SE)version=Oracle GraalVM Enterprise Edition:20.3.8; version=Oracle GraalVM Enterprise Edition:21.3.4; version=Oracle GraalVM Enterprise Edition:22.3.0; version=Oracle Java SE:11.0.17; version=Oracle Java SE:17.0.5; version=Oracle Java SE:19.0.1

Published CVSS scores

5.3Oracle CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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